1. Field of the Invention
The present invention relates to a sheet conveying device for conveying a sheet.
2. Description of the Related Art
There exists a sheet conveying device which causes a pickup roller to feed document sheets or the like stacked on a stacking table and a sheet separating section including a separation roller and a separation pad to separate each sheet, and then feeds it to an image reading apparatus. Some sheet conveying devices of this type have a stopper between the pickup roller and the sheet separating section to limit feeding of the sheets stacked on the stacking table. For example, Japanese Patent Laid-Open No. 6-305595 discloses a technique of extracting a rotating force from the separation shaft with the separation roller fixed on it, and transferring the rotating force to a swing lever via a clutch spring to make the lever pivot, thereby causing a driving shaft with the stopper fixed on it to pivot following the pivotal movement of the swing lever.
In the technique disclosed in Japanese Patent Laid-Open No. 6-305595, however, the stopper needs to be driven against the self weight of the sheets stacked on the stacking table. To do this, it is necessary to increase the drag torque of the clutch spring and also increase the driving torque of the driving source. The load on the stopper becomes heavier especially when a number of sheets are stacked on the stacking table.